The Fifth International Symposium on Selenium in Biology and Medicine will be held in Nashville at Vanderbilt University on July 20-23, 1992. The major purpose of this meeting is to promote communication and collaboration among researchers throughout the world who are working on biological aspects of selenium. There will be a special focus on selenium and human health. A session on selenium in the environment is planned. In the three years since the fourth symposium in Tubingen, Germany, great progress has been made in the molecular biology and biochemistry of selenium. The mechanism of its incorporation into protein as selenocysteine has been characterized and several new selenoproteins have been identified and characterized. Mechanisms of the regulation of selenoprotein synthesis are being elucidated. Selenium is a well known antioxidant through the selenoenzyme glutathione peroxidase but there are strong indications that it has additional antioxidant effects. Also, recent reports document a role in thyroid hormone metabolism. Application of these findings to the study of human disease will be helpful. Selenium deficiency is necessary for the development of the cardiomyopathy known as Keshan disease, and evidence has been presented showing that selenium can influence the development of cancer in model systems. Linking these effects with biochemical functions of the element remains a challenge and can be facilitated by bringing together basic and clinical scientists in meetings such as this one. The basic advances have also provided new means for the evaluation of selenium status which can be applied to humans and which will be helpful in answering human health questions. The fifth symposium is a continuation of a series of international meetings on selenium. The first one was held in 1966 and the other three were held at four-year intervals beginning in 1980. The last two were held outside the U.S. A 10-member organizing committee has been formed and a 3-1/2 day venue is planned. The proceedings will be published. Partial support is requested for travel expenses for invited speakers and for other costs of the meeting.